Since World War II, an explosive known as C-4 has been widely used for military and civilian operations, such as excavation and demolition. C-4 contains an environmental contaminant known 1,3,5-Trinitroperhydro-1,3,5-triazine (RDX). RDX can migrate through soil and contaminate underlying groundwater aquifers and may be harmful to humans at relatively low levels. The US Environmental Protection Agency (EPA) has established a lifetime health advisory guidance level of 0.002 milligrams per liter (mg/L) for RDX in drinking water. The EPA has identified more than thirty RDX contaminated sites on its list of national clean-up priorities.
Manufacturers have begun to substitute a more stable chemical explosive, 3-Nitro-1,2,4-triazol-5-one (nitrotriazolone or NTO), for RDX. However, NTO faces similar problems with contamination. The US Center for Disease Control mandates reporting spills of any amount of NTO under the National Toxic Substance Incidents Program (NTSIP), requiring rapid testing of any areas where NTO may be present.
There are several problems known in the art for testing for the presence of RDX and NTO to make determinations relevant to a potential need for reporting and remediation. RDX and NTO concentrations are discrete particles that are irregularly dispersed throughout the soil. The concentration of samples from adjacent areas may vary considerably. Current RDX and NTO testing methods are intended to provide data about precise quantities of RDX and NTO using highly sensitive, off-site instrumentation to separately test each sample. This type of high-sensitivity off-site testing is not appropriate for wide scale EPA and private environmental remediation projects. The lack of rapid testing prevents immediate reporting under the NTSIP and often does not yield the necessary type of data for evaluating dispersal patterns over potentially contaminated site.
For purposes of reporting, planning, and remediation, it is important to be able to test many samples to determine the presence or absence of contaminants over a dispersed area and patterns of dispersal. Current high-sensitivity testing methods performed off-site are costly and prone to delay because they cannot be performed in situ.
There is an unmet need in the art for a rapid, in situ test for RDX and NTO contamination.